Many of the patients he sees are suffering the effects of smoking.
"I don't operate on smokers," he said. "I tell cigarette smokers that I can operate on you, I get paid the same. And you might even do well. But it's the wrong thing to do. So I refuse to operate on you until you stop smoking."
He promises to do whatever he can to help patients stop smoking.
"In my entire career, I've never had a patient not stop," he said.
Unfortunately, many resume smoking after surgery despite follow-up treatment.
"I recognize that the average smoker stops and then starts again six times before they succeed," he said. "At least I took care of one of 'em."
Oz says the hardest thing for a surgeon to come to terms with is someone who's been through surgery and still hasn't responded to the message about exercise and weight.
Peter Calafati, a 52-year-old who had a coronary bypass five months ago, still has trouble with exercise -- and some of that stomach is back.
"I look at you and I blame myself," Oz told him. "I say, I must have walked him through all the details of open heart surgery but … I didn't get into his heart and get him to appreciate why I feel so passionately about doing these things."
"It's laziness on that area, you know?" Calafati said. "It wasn't like a life-shattering moment for me, it was almost somewhat expected."
"That is actually the most cogent answer I have ever gotten to that question," Oz said, adding that coronary bypass never used to be done on patients as young as Calafati or others he treats.
"It's being done on 25-year-olds," he said.
The rise in surgical procedures may be good for business for a surgeon, but Oz is hoping for the opposite.
"The main reason that I really wanted you to come is to put me out of business," Oz said in the operating room. "Because although this is extremely fulfilling and I really do enjoy it a lot at its very foundation, you walk in there and you realize my goodness, this didn't have to happen."
Preventative medicine will be the focus of "The Dr. Oz Show," which premieres on Sept. 14, 2009.